JP2004214173A - Method for manufacturing membrane-electrode structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing membrane-electrode structure excellent in adhesion between an electrode catalyst layer and a diffusion layer, a solid polymer electrolyte membrane fuel cell equipped with the structure, electric devices and apparatuses for transportation using the fuel cell. <P>SOLUTION: Catalyst paste is spread on a support sheet 2 and dried to form an electrode catalyst layer 3. This layer 3 and 3 are transferred on to both sides of a polymer electrolyte membrane 1 by means of thermal transfer. The first coat of slurry is applied on a basic layer of carbon 6 and dried to form a first underlayer 7 and the second coat of slurry is applied on the underlayer 7 and dried to form a second underlayer 8 of which surface roughness is 40μm or less at maximum height Rmax, which provides a diffusion electrode 5. The underlayer 8 of the diffusion electrode 5 is pressed on the electrode catalyst layer 3 and heated to integrate them into a pile of layers. The underlayer 8 has surface roughness in which ratio of the superficial area of the underlayer 8 to unit area is 1.25 or less. The second slurry contains materials having fine cavities. The underlayer 8 is formed so that the pressure difference between two sides of diffusion electrode 4 is within the range of 100 to 300 mmAq. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a membrane-electrode structure used in a polymer electrolyte fuel cell.

  While petroleum resources are being depleted, environmental problems such as global warming due to consumption of fossil fuels are becoming more serious. In view of this, fuel cells have attracted attention as clean electric power sources for electric motors that do not generate carbon dioxide, and have been widely developed, and some have begun to be put into practical use. When the fuel cell is mounted on an automobile or the like, a solid polymer fuel cell using a polymer electrolyte membrane is preferably used because a high voltage and a large current are easily obtained.

  As shown in FIG. 4, as a membrane-electrode structure used in the polymer electrolyte fuel cell, catalyst particles in which a catalyst such as platinum is supported on carbon particles such as carbon black are integrated by an ion-conductive polymer binder. And a pair of electrode catalyst layers 3 and 3 formed by the above-described process. The ion-conductive polymer electrolyte membrane 1 is sandwiched between the two electrode catalyst layers 3 and 3. There is known a membrane-electrode structure 10 in which diffusion electrodes 5 and 5 are stacked on the electrode 3. The membrane-electrode structure 10 further constitutes a polymer electrolyte fuel cell by laminating a separator also serving as a gas passage on each of the diffusion electrodes 5 and 5.

  In the polymer electrolyte fuel cell, one electrode catalyst layer 3 is used as a fuel electrode, and a reducing gas such as hydrogen or methanol is introduced through the diffusion electrode 5 on the fuel electrode side, and the other electrode catalyst layer 3 is supplied with oxygen. An oxidizing gas such as air or oxygen is introduced as a pole through the diffusion electrode 5 on the oxygen electrode side. In this manner, on the fuel electrode side, protons are generated from the reducing gas by the action of the catalyst contained in the electrode catalyst layer 3, and the protons are passed through the polymer electrolyte membrane 1 to the oxygen electrode side. It moves to the electrode catalyst layer 3. Then, the protons react with the oxidizing gas introduced into the oxygen electrode in the electrode catalyst layer 3 on the oxygen electrode side by the action of a catalyst contained in the electrode catalyst layer 3 to generate water. Therefore, a current can be taken out by connecting the fuel electrode and the oxygen electrode with a conducting wire.

  By the way, in the membrane-electrode structure 10, the carbon paper 5 forming the diffusion electrode 4 is formed by forming carbon fibers into a sheet, and the surface thereof has irregularities. If the carbon paper 5 and the electrode catalyst layer 3 are directly laminated on the layer 3, sufficient adhesion cannot be obtained. Therefore, an underlayer 6 containing an electron conductive material such as carbon black and a water-repellent material such as polytetrafluoroethylene (PTFE) particles is formed on the carbon paper 5 to reduce unevenness on the surface of the diffusion electrode 4. Then, the membrane-electrode structure 10 is manufactured by laminating the electrode catalyst layer 3 via the underlayer 6 and pressing it under heating (for example, see Patent Document 1).

However, in the conventional manufacturing method, the effect of reducing the unevenness of the surface of the diffusion electrode 4 by the base layer 6 is insufficient, and sufficient adhesion between the electrode catalyst layer 3 and the diffusion electrode 5 can be obtained. There is an inconvenience that there are things that cannot be done. If sufficient adhesion between the electrode catalyst layer 3 and the diffusion electrode 5 cannot be obtained, when a polymer electrolyte fuel cell is constructed using the membrane-electrode structure 10, a resistance overvoltage is reduced. And the power generation performance decreases.
JP-A-3-84866

  An object of the present invention is to provide a method for producing a membrane-electrode structure capable of solving such disadvantages and obtaining excellent adhesion between an electrode catalyst layer and a diffusion electrode.

  In order to achieve such an object, the method for producing a membrane-electrode structure of the present invention comprises applying a catalyst paste containing a catalyst-supporting electron conductive material and an ion conductive material onto a sheet-like support, and drying the paste. Forming an electrode catalyst layer, and thermally transferring the electrode catalyst layer to both sides of the polymer electrolyte membrane to form a laminate in which the electrode catalyst layer is bonded to both sides of the polymer electrolyte membrane. A first slurry containing a water-repellent material and an electron conductive material is coated on a carbon base material layer and dried to form a first underlayer, and then the electron conductive material and the ion conductive material are Is coated on the first underlayer, and dried to form a second underlayer having a maximum surface roughness height Rmax of 40 μm or less. Forming a diffusion electrode composed of both base layers; and forming the electrode catalyst layer of the laminate. A step of laminating the diffusion electrode formed in advance via the second underlayer, pressing the layer under heating, and integrating the laminated body with the diffusion electrode. .

  In the production method of the present invention, when forming a diffusion electrode, first, a first underlayer is formed on a carbon base material layer, and a second slurry is further applied on the first underlayer, followed by drying. Thus, a second underlayer is formed. The second underlayer can be coated on the first underlayer and dried to obtain excellent adhesion with the first underlayer. Further, since the second underlayer contains an electron conductive material and an ion conductive material, the maximum height Rmax of the surface roughness can be set to 40 μm or less, and the unevenness of the surface of the diffusion electrode can be reduced. Can be sufficiently reduced.

  Next, in the manufacturing method of the present invention, the diffusion electrode, in which the second underlayer is formed in advance on the first underlayer as described above, is connected to the electrode catalyst layer through the second underlayer. And pressed under heating. Since the surface of the diffusion electrode is reduced in unevenness by the second underlayer, it is stacked on the electrode catalyst layer via the second underlayer as described above, and is pressed under heating. And the electrode catalyst layer can be securely joined, and excellent adhesion can be obtained between the diffusion electrode and the electrode catalyst layer.

  When the maximum height Rmax of the surface roughness exceeds 40 μm, the second underlayer cannot sufficiently obtain the effect of reducing irregularities on the surface of the diffusion electrode.

  Further, the manufacturing method of the present invention is characterized in that the second underlayer has a surface roughness having a ratio of a surface area to a unit area of 1.25 or less. Since the second underlayer has the surface roughness, the unevenness on the surface of the diffusion electrode can be more reliably reduced. When the second underlayer has a surface roughness in which the ratio of the surface area to the unit area exceeds 1.25, the effect of reducing unevenness on the surface of the diffusion electrode may not be sufficiently obtained.

  Further, the production method of the present invention is characterized in that the second slurry contains a pore forming material. Examples of the pore forming material include carbon fibers. The second slurry containing the pore-forming material is applied on the first underlayer, and dried to form the second underlayer having pores formed between the carbon fibers. And the reducing gas or the oxidizing gas can be diffused through the pores.

Also, in the manufacturing method of the present invention, when the air flows at a flow rate of 0.5 liter / cm ² / min in the thickness direction of the diffusion electrode, the two underlayers may be in contact with one surface of the diffusion electrode. It is characterized in that it is formed so that the differential pressure with the other surface is in the range of 100 to 300 mmAq. According to the production method of the present invention, when the differential pressure is in the range, the unevenness of the surface of the diffusion electrode is reduced, and a film having excellent adhesion between the diffusion electrode and the electrode catalyst layer is provided. An electrode structure can be obtained.

  When the differential pressure is less than 100 mmAq, the application amount of the second slurry is small, and the effect of reducing the unevenness of the diffusion electrode surface may not be sufficiently obtained. When the pressure difference exceeds 300 mmAq, the application amount of the second slurry is sufficient and the irregularities on the surface of the diffusion electrode can be sufficiently reduced, but the gas diffusion property of the diffusion electrode becomes low. In some cases, sufficient power generation performance cannot be obtained due to the formed membrane-electrode structure.

  The present invention also relates to a polymer electrolyte fuel cell using the membrane-electrode structure obtained by the above manufacturing method. The polymer electrolyte fuel cell of the present invention can be used, for example, as a power supply, a backup power supply, and the like for electric devices such as personal computers and mobile phones. Further, the polymer electrolyte fuel cell of the present invention can be used, for example, as a power source for transportation equipment such as automobiles and submarines.

  Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. FIG. 1 is a manufacturing process diagram schematically showing a method for manufacturing the membrane-electrode structure of the present embodiment, FIG. 2 is a graph showing the power generation performance of the membrane-electrode structure of the present embodiment, and FIG. 4 is a graph showing a relationship between a pressure difference of a diffusion electrode of the membrane-electrode structure of the embodiment and power generation performance.

  In the production method of the present embodiment, first, a sulfonated polyarylene-based polymer is prepared. In addition, in this specification, a "sulfonated polyarylene-based polymer" means a sulfonated product of a polymer having the following formula.

前記２価の有機基としては、−ＣＯ−、−ＣＯＮＨ−、−（ＣＦ_２）_ｐ−（ｐは１〜１０の整数）、−Ｃ（ＣＦ_３）_２−、−ＣＯＯ−、−ＳＯ−、−ＳＯ_２−等の電子吸引性基、−Ｏ−、−Ｓ−、−ＣＨ＝ＣＨ−、−Ｃ≡Ｃ−等の基、さらに次式で表される電子供与性基等を挙げることができる。

Examples of the divalent organic group, -CO -, - CONH -, - (CF 2) p - (p is an integer of from 1 to _{10), - C (CF 3)} 2 -, - COO -, - SO- , -SO ₂ - electron-withdrawing group such as, -O -, - S -, - CH = CH -, - C≡C- such groups further include an electron-donating groups represented by the following formula Can be.

また、前記２価の電子吸引性基としては、−ＣＯ−、−ＣＯＮＨ−、−（ＣＦ_２）_ｐ−（ｐは１〜１０の整数）、−Ｃ（ＣＦ_３）_２−、−ＣＯＯ−、−ＳＯ−、−ＳＯ_２−等の基を挙げることができる。

Further, as the divalent electron attractive group, -CO -, - CONH -, - (CF 2) p - (p is an integer of from 1 to _{10), - C (CF 3)} 2 -, - COO- , -SO -, - SO ₂ - group and the like.

  The sulfonated polyarylene-based polymer can be prepared, for example, by adding concentrated sulfuric acid to the polyarylene-based polymer represented by the formula (1) to perform sulfonation.

式（１）において、ｍ：ｎ＝０．５〜１００：９９．５〜０であり、ｌは１以上の整数である。

In the formula (1), m: n = 0.5 to 100: 99.5 to 0, and 1 is an integer of 1 or more.

  The polyarylene-based polymer represented by the formula (1) can be prepared, for example, as follows. First, 6,7.3 parts by weight of 2,2-bis (4-hydroxyphenyl) -1,1,1,3,3,3-hexafluoropropane (bisphenol AF) and 53.5 parts by weight of 4,4′-dichlorobenzophenone And 34.6 parts by weight of potassium carbonate are heated in a mixed solvent of N, N-dimethylacetamide and toluene under a nitrogen atmosphere and reacted at 130 ° C. while stirring. While removing water generated by the reaction by azeotropic distillation with toluene and removing the water outside the system, the reaction is allowed to proceed until almost no generation of water is recognized, and then the reaction temperature is gradually increased to 150 ° C. to remove the toluene. After continuing the reaction at 150 ° C. for 10 hours, 3.3 parts by weight of 4,4′-dichlorobenzophenone is added, and the reaction is further performed for 5 hours.

  After cooling the obtained reaction solution, the precipitate of the by-product inorganic compound is removed by filtration, and the filtrate is poured into methanol. The precipitated product is separated by filtration, recovered, dried and then dissolved in tetrahydrofuran. By reprecipitating this with methanol, an oligomer represented by the following formula (2) is obtained. In the oligomer of the formula (2) obtained as described above, the average value of 1 is, for example, 18.9.

次に、式（２）で表されるオリゴマー２８．４重量部、２，５−ジクロロ−４’−（４−フェノキシ）フェノキシベンゾフェノン２９．２重量部、ビス（トリフェニルホスフィン）ニッケルジクロリド１．３７重量部、ヨウ化ナトリウム１．３６重量部、トリフェニルホスフィン７．３４重量部、亜鉛末１１．０重量部をフラスコに取り、乾燥窒素置換する。次に、Ｎ−メチル−２−ピロリドンを加え、８０℃に加熱して撹拌下に４時間重合を行う。重合溶液をテトラヒドロフランで希釈し、塩酸／メタノールで凝固させ回収する。回収物に対してメタノール洗浄を繰り返し、テトラヒドロフランに溶解する。これをメタノールで再沈殿して精製し、濾集したポリマーを真空乾燥することにより、式（１）で表されるポリアリーレン系ポリマーが得られる。

Next, 28.4 parts by weight of the oligomer represented by the formula (2), 29.2 parts by weight of 2,5-dichloro-4 ′-(4-phenoxy) phenoxybenzophenone, and bis (triphenylphosphine) nickel dichloride. 37 parts by weight, 1.36 parts by weight of sodium iodide, 7.34 parts by weight of triphenylphosphine, and 11.0 parts by weight of zinc dust are placed in a flask and purged with dry nitrogen. Next, N-methyl-2-pyrrolidone is added, and the mixture is heated to 80 ° C. and polymerized for 4 hours with stirring. The polymerization solution is diluted with tetrahydrofuran and solidified and recovered with hydrochloric acid / methanol. The collected product is repeatedly washed with methanol and dissolved in tetrahydrofuran. This is purified by reprecipitation with methanol, and the polymer collected by filtration is vacuum-dried to obtain a polyarylene-based polymer represented by the formula (1).

  The sulfonation of the polyarylene-based polymer represented by the formula (1) can be performed, for example, by adding 96% sulfuric acid to the polyarylene-based polymer and stirring for 24 hours under a nitrogen stream.

  As the sulfonated polyarylene-based polymer, a sulfonated polyarylene-based polymer represented by the following formula (3) may be used instead of the sulfonated polyarylene-based polymer represented by formula (1).

式（３）で表される共重合体は、次式（４）で表されるモノマーと、前記式（２）で表されるオリゴマーとを共重合させた後、スルホン酸エステル基（−ＳＯ₃ＣＨ（ＣＨ₃）Ｃ₂Ｈ₅）を加水分解してスルホン酸基（−ＳＯ₃Ｈ）とすることにより得ることができる。

The copolymer represented by the formula (3) is obtained by copolymerizing a monomer represented by the following formula (4) and an oligomer represented by the above formula (2), and then a sulfonic acid ester group (-SO ₃ CH (CH ₃ ) C ₂ H ₅ ) by hydrolysis to form a sulfonic acid group (—SO ₃ H).

本実施形態の製造方法では、次に、前記スルホン化ポリアリーレン系ポリマーをＮ−メチルピロリドン等の溶媒に溶解して、高分子電解質溶液を調製する。そして、前記高分子電解質溶液からキャスト法により成膜し、オーブンにて乾燥することにより、図１（ａ）に示すように、例えば乾燥膜厚３０〜５０μｍの高分子電解質膜１を形成する。

Next, in the production method of the present embodiment, the sulfonated polyarylene-based polymer is dissolved in a solvent such as N-methylpyrrolidone to prepare a polymer electrolyte solution. Then, a film is formed from the polymer electrolyte solution by a casting method and dried in an oven to form a polymer electrolyte membrane 1 having a dry film thickness of 30 to 50 μm, for example, as shown in FIG.

  Next, catalyst particles such as platinum are supported on an electron conductive material such as carbon black (furnace black) in a weight ratio of catalyst: electron conductive material = 1: 1, for example. Next, the catalyst particles are added to a solution of a perfluoroalkylenesulfonic acid polymer compound (for example, Nafion (trade name) manufactured by DuPont) as an ion-conductive material solution, for example, catalyst particles: ion-conductive material = 1: 1. To prepare a catalyst paste.

Next, the catalyst paste is screen-printed on the fluororesin-based release film 2 shown in FIG. 1 (b) so that the catalyst amount becomes, for example, 0.5 mg / cm ² , for example, at 100 ° C. for 30 minutes. After drying, the electrode catalyst layer 3 is formed. Next, as shown in FIG. 1C, the polymer electrolyte membrane 1 is sandwiched between a pair of electrode catalyst layers 3 and 3, and hot pressed from above the fluororesin release film 2.

  The hot press is performed, for example, at a temperature in the range of 100 to 150 ° C., applying a surface pressure in the range of 1 to 5 MPa, and for 5 to 30 minutes. As a result, the electrode catalyst layer 3 is transferred to the polymer electrolyte membrane 1 and joined to the polymer electrolyte membrane 1. Next, when the fluororesin release film 2 is peeled off, a laminate 4 in which the polymer electrolyte membrane 1 is sandwiched between the pair of electrode catalyst layers 3 and 3 is obtained as shown in FIG.

  Next, the diffusion electrode 5 shown in FIG. 1E is formed. The diffusion electrode 5 is formed by first mixing polytetrafluoroethylene (PTFE) particles as a water-repellent material and carbon black as an electron-conductive material, for example, by weight of water-repellent material: electron-conductive material = 6: 4. A first slurry is prepared by uniformly dispersing the mixture obtained by mixing at a ratio in ethylene glycol. Then, the first slurry is applied on carbon paper 6 as a carbon base material layer and dried to form a first underlayer 7 having a dry film thickness of 10 to 40 μm, for example.

Next, carbon black as an electron conductive material and carbon fiber (for example, VGCF (trade name) manufactured by Showa Denko KK) as a pore forming material were mixed with perfluoroalkylenesulfonic acid as an ion conductive material solution. A polymer compound (for example, Nafion (trade name) manufactured by DuPont) is added to a solution and mixed, for example, in a weight ratio of electron conductive material: pore forming material: ion conductive material = 1: 1: 1, and then mixed. The second slurry is prepared by irradiating a sound wave, for example, for 10 minutes to uniformly disperse. Then, the second slurry is applied on the first underlayer 7 and dried at a temperature of 100 ° C. for 30 minutes, for example, so that the applied amount after drying is 0.1 to 1.2 mg / cm. ^{A second} underlayer 8 is formed.

  As a result, the diffusion electrode 5 including the first underlayer 7 on the carbon paper 6 and further including the second underlayer 8 on the underlayer 7 is formed. Since the underlayer 8 is formed of the second slurry containing the carbon fibers, it is a porous body having pores formed in gaps between the carbon fibers.

  After the diffusion electrode 5 is formed, the diffusion electrode 5 is laminated on the electrode catalyst layer 3 via the second underlayer 8 as shown in FIG. Press. The hot press is performed, for example, at a temperature in the range of 100 to 150 ° C., applying a surface pressure in the range of 1 to 5 MPa, and for 5 to 30 minutes. As a result, a membrane-electrode structure 9 in which the diffusion electrode 5 is bonded to the electrode catalyst layer 3 via the second underlayer 8 is obtained.

Next, using a sulfonated polyarylene-based polymer represented by the formula (1), the membrane-electrode structure 9 (implementation) in which the applied amount of the second underlayer 8 after drying was 0.35 mg / cm ^2. Example 1), the membrane-electrode structure 9 (Example 2) in which the coating amount was 0.70 mg, and the membrane-electrode structure 10 shown in FIG. 4 where no second underlayer 8 was formed (Comparative Example) Regarding 1), the maximum height Rmax of the surface roughness, the ratio of the surface area to the unit area, the diffusion electrode 4 when air flows at a flow rate of 0.5 L / cm ² / min in the thickness direction of the diffusion electrode 4 The differential pressure between one side and the other side was measured. Table 1 shows the results.

  Further, power was generated using the membrane-electrode structure 9 of Examples 1 and 2 and the membrane-electrode structure 10 of Comparative Example 1. FIG. 2 shows a change in the terminal voltage with respect to the current density at this time.

表１と図２とから、表面粗さの最大高さＲmaxが４０μｍ以下であり、単位面積に対する表面積の比が１，２５以下であり、拡散電極４の一方の面と他方の面との差圧が１００〜３００ｍｍＡｑの範囲にある実施例１，２の膜−電極構造体９によれば、前記Ｒmaxが４０μｍを超え、単位面積に対する表面積の比が１，２５を超え、前記差圧が１００ｍｍＡｑ未満である比較例１の膜−電極構造体１０よりも、優れた発電性能を得ることができることが明らかである。

From Table 1 and FIG. 2, the maximum height Rmax of the surface roughness is 40 μm or less, the ratio of the surface area to the unit area is 1,25 or less, and the difference between one surface and the other surface of the diffusion electrode 4 is shown. According to the membrane-electrode structure 9 of Examples 1 and 2 in which the pressure is in the range of 100 to 300 mmAq, the Rmax exceeds 40 μm, the ratio of the surface area to the unit area exceeds 1, 25, and the differential pressure is 100 mmAq. It is clear that a superior power generation performance can be obtained as compared with the membrane-electrode structure 10 of Comparative Example 1, which is less than.

  As shown in FIG. 2, since excellent power generation performance is obtained in the membrane-electrode structure 9 (Examples 1 and 2) on which the second underlayer 8 is formed, the membrane-electrode structure 9 has an electrode catalyst layer. It is clear that excellent adhesion was obtained between 3 and the diffusion electrode 5.

Next, the applied amount of the second underlayer 8 after drying is varied in the range of 0 to 12 mg / cm ² , and air is applied at a flow rate of 0.5 liter / cm ² / min in the thickness direction of the diffusion electrode 4. The membrane-electrode assembly 9 in which the differential pressure between one surface and the other surface of the diffusion electrode 4 when flowing was varied in the range of 50 to 350 mmAq was manufactured, and power generation was performed. Wherein each membrane - the electrode structure 9, shown with the differential pressure, current density 0.7 A ^/ cm 2, the relationship between the terminal voltage when the 1.4A / cm ² in FIG.

  From FIG. 3, according to the membrane-electrode structure 9 in which the differential pressure is in the range of 100 to 300 mmAq, it is possible to obtain power generation performance superior to the membrane-electrode structure 9 in which the differential pressure is less than 100 mmAq or exceeds 300 mmAq. It is clear that can be done.

  In this embodiment, the case where the polymer electrolyte membrane 1 made of a sulfonated polyarylene-based polymer is used is described as an example. However, the polymer electrolyte membrane 1 may be a polymer having ion conductivity. Examples of such a polymer include a perfluoroalkylenesulfonic acid polymer compound (for example, Nafion (trade name) manufactured by DuPont).

The manufacturing process figure which shows typically an example of the manufacturing method of the membrane-electrode structure of this invention. 5 is a graph showing an example of the power generation performance of the membrane-electrode structure of the present invention. 5 is a graph showing an example of the power generation performance of the membrane-electrode structure of the present invention. Explanatory sectional view showing a configuration example of a conventional membrane-electrode structure.

Explanation of reference numerals

  DESCRIPTION OF SYMBOLS 1 ... Polymer electrolyte membrane, 2 ... Sheet-like support, 3 ... Electrode catalyst layer, 4 ... Laminated body, 5 ... Diffusion electrode, 6 ... Carbon base material layer, 7 ... First underlayer, 8 ... Second Underlayer, 9 ... film-electrode structure.

Claims (7)

A step of applying a catalyst paste containing an electron-conductive material and an ion-conductive material carrying a catalyst on a sheet-like support, and drying to form an electrode catalyst layer,
Thermally transferring the electrode catalyst layer to both sides of the polymer electrolyte membrane, and forming a laminate in which the electrode catalyst layer is bonded to both sides of the polymer electrolyte membrane;
A first slurry containing a water-repellent material and an electron conductive material is applied on a carbon substrate layer and dried to form a first underlayer, and then the electron conductive material and the ion conductive material are mixed. A second slurry including the second base layer is applied on the first base layer and dried to form a second base layer having a maximum surface roughness Rmax of 40 μm or less. Forming a diffusion electrode comprising an underlayer,
The diffusion electrode formed in advance on the electrode catalyst layer of the laminate is laminated via the second underlayer, and pressed under heating to integrate the laminate with the diffusion electrode. And a method for producing a membrane-electrode structure.   The method according to claim 1, wherein the second underlayer is formed so as to have a surface roughness having a surface area ratio to a unit area of 1.25 or less.   The method for manufacturing a membrane-electrode structure according to claim 1 or 2, wherein the second slurry contains a pore-forming material. When air flows at a flow rate of 0.5 liter / cm ² / min in the thickness direction of the diffusion electrode, the pressure difference between one surface and the other surface of the diffusion electrode is 100 The method for manufacturing a membrane-electrode structure according to any one of claims 1 to 3, wherein the film-electrode structure is formed so as to fall within a range of -300 mmAq. A step of applying a catalyst paste containing an electron-conductive material and an ion-conductive material carrying a catalyst on a sheet-like support, and drying to form an electrode catalyst layer,
Thermally transferring the electrode catalyst layer to both sides of the polymer electrolyte membrane, and forming a laminate in which the electrode catalyst layer is bonded to both sides of the polymer electrolyte membrane;
A first slurry containing a water-repellent material and an electron conductive material is applied on a carbon substrate layer and dried to form a first underlayer, and then the electron conductive material and the ion conductive material are mixed. A second slurry including the second base layer is applied on the first base layer and dried to form a second base layer having a maximum surface roughness Rmax of 40 μm or less. Forming a diffusion electrode comprising an underlayer,
The diffusion electrode formed in advance on the electrode catalyst layer of the laminate is laminated via the second underlayer, and pressed under heating to integrate the laminate with the diffusion electrode. Comprising a membrane-electrode structure obtained by a production method comprising the steps of: A step of applying a catalyst paste containing an electron-conductive material and an ion-conductive material carrying a catalyst on a sheet-like support, and drying to form an electrode catalyst layer,
Thermally transferring the electrode catalyst layer to both sides of the polymer electrolyte membrane, and forming a laminate in which the electrode catalyst layer is bonded to both sides of the polymer electrolyte membrane;
A first slurry containing a water-repellent material and an electron conductive material is applied on a carbon substrate layer and dried to form a first underlayer, and then the electron conductive material and the ion conductive material are mixed. A second slurry including the second base layer is applied on the first base layer and dried to form a second base layer having a maximum surface roughness Rmax of 40 μm or less. Forming a diffusion electrode comprising an underlayer,
The diffusion electrode formed in advance on the electrode catalyst layer of the laminate is laminated via the second underlayer, and pressed under heating to integrate the laminate with the diffusion electrode. Electrical equipment using a polymer electrolyte fuel cell provided with a membrane-electrode structure obtained by a manufacturing method comprising the steps of: A step of applying a catalyst paste containing an electron-conductive material and an ion-conductive material carrying a catalyst on a sheet-like support, and drying to form an electrode catalyst layer,
Thermally transferring the electrode catalyst layer to both sides of the polymer electrolyte membrane, and forming a laminate in which the electrode catalyst layer is bonded to both sides of the polymer electrolyte membrane;
A first slurry containing a water-repellent material and an electron conductive material is applied on a carbon substrate layer and dried to form a first underlayer, and then the electron conductive material and the ion conductive material are mixed. A second slurry including the second base layer is applied on the first base layer and dried to form a second base layer having a maximum surface roughness Rmax of 40 μm or less. Forming a diffusion electrode comprising an underlayer,
The diffusion electrode formed in advance on the electrode catalyst layer of the laminate is laminated via the second underlayer, and pressed under heating to integrate the laminate with the diffusion electrode. Transport equipment using a polymer electrolyte fuel cell provided with a membrane-electrode structure obtained by a manufacturing method comprising the steps of:

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